This Phase I project will evaluate the feasibility of developing an exposure monitor for particles in the PM2.5 and PM10 size ranges, and for volatile organic compounds (VOCs), at threshold levels for children's health effects. The proposed device will use aerodynamic particle properties for concentration and separation into discrete size bins and will enable the use of low-cost optical PM sensors to measure low ambient particulate concentrations. Real-time measurements of the mass of sampled particles will provide size- and time-resolved exposure data. This device will also collect the sampled particles in micro-channel collectors for subsequent laboratory analysis and characterization of each size fraction. In addition, the proposed monitor will collect VOCs in a sorbent bed preconcentrator. Following collection, the sample will be thermally desorbed and delivered to a commercially available low cost VOC sensor. The use of the preconcentrator will enhance the detection limit of the sensor by at least two orders of magnitude allowing the detection of VOC vapors at parts per billion threshold levels. Coupled to automated data recording equipment, this monitor will provide time- resolved measurements of low level ambient particulate and VOC pollution. The specific aims of the proposed project are to: 1. Demonstrate real-time measurement of ambient aerosols at exposure threshold levels using an aerodynamic lens aerosol concentrator and a compact, low-cost optical dust sensor. 2. Demonstrate classification of concentrated ambient aerosols into PM2.5 and PM10 size fractions using an aerodynamic size classifier, and demonstrate separate measurement of the PM2.5 and PM10 concentrations at health effect threshold levels using low-cost optical dust sensors. 3. Demonstrate the ability to pre-concentrate VOCs in a sorbent bed, to selectively desorb VOC components of differing volatilities, and detect these individual components at health effect threshold levels using a low-cost detector. Building on its extensive experience and expertise in aerosol and vapor sampling and detection, and using its wide array of aerosol instrumentation and its large aerosol chamber, Enertechnix and its collaborators at the University of Washington will investigate the feasibility of each of the elements of the proposed exposure monitor. The proposed exposure monitor will provide researchers and regulators with a low-cost device that can provide high temporal resolution of particulate and VOC exposure at threshold levels for children's health effects;it will aid researchers in investigating the connection between health effects and environmental exposure, and could serve as a warning device for populations sensitive to particle pollution or for workers in environments with high particulate hazards. PUBLIC HEALTH RELEVANCE: Exposure to environmental agents such as airborne particles and volatile organic compounds can trigger or exacerbate diseases such as asthma, cardiovascular disease, cancer, and neurological disorders, but there is still much uncertainty about the causal relationships between exposure and disease. Therefore, there is an ongoing need to conduct studies to investigate the impact of environmental and industrial particulate and VOC contaminants on the health of the population, and for better exposure monitors for particulate and VOCs employing light-weight, low-cost components. Such monitors would provide information required to further our understanding of the causal relationships between exposure and health, and could be used to detect excessive levels of particlate and VOCs in schools, daycare facilities, homes, offices and industrial workplaces, indicating the need for remedial action to eliminate these hazardous conditions.